William O Brien State Park

Marine On Saint Croix, Minnesota· Campsite openings, cancellations & sold-out date alerts

State ParksSmall parkWatched around the clock

Sold out for your dates? We'll tell you the second a site opens.

Cancellations at William O Brien State Park get rebooked in minutes. We check Minnesota State Parks around the clock and alert you before the crowd refreshes the page.

Set an alert for Marine On Saint Croix$9.99/mo — why we charge

The alert

Here's what lands the second a site opens.

The moment a campsite frees up at William O Brien State Park, we send it — with the dates and a one-tap link to book it on Minnesota State Parks before anyone else. Most alerts go out within minutes.

EmailPushText — coming soon

How GetParkAlerts works

  1. 01

    Set your alert for William O Brien State Park

    Tell us your dates and how many nights. Takes about 30 seconds.

  2. 02

    We watch, around the clock

    We check Minnesota State Parks every few minutes for the cancellations that vanish before most people notice.

  3. 03

    You get the alert first

    Email or push the instant a matching site frees up. You book it directly with the park — we just get you there first.

How booked is William O Brien State Park?

as of July 23

Sites are open right now across the next 4 weekends — but that changes fast at a state park. We check William O Brien State Parkaround the clock, so the moment your weekend fills up and a cancellation reopens it, you'll be first to know.

Jul 25Sites open
Aug 1Sites open
Aug 8Sites open
Aug 15Sites open

Weekend (Saturday-night) availability, checked directly against the reservation system.

Park type

State Parks

Small park

Online booking

Available on Minnesota State Parks

Official state reservation system

Alert coverage

Checked around the clock

Openings, cancellations & new dates

Where William O Brien State Park is

16821 O'Brien Trail North

Marine On Saint Croix, MN 55047

45.2254, -92.7636

Get directions

Getting a campsite at William O Brien State Park

How do I get a campsite at William O Brien State Park when it's sold out?

Cancellations happen constantly — the trick is being first to know. Set an alert for your dates and we'll watch William O Brien State Park on Minnesota State Parks around the clock, then notify you the moment a site opens. Alerts run on a Pro subscription ($9.99/mo, cancel anytime).

When do campsites usually open up at William O Brien State Park?

Whenever someone cancels. Most reservation systems refund less the closer you get to arrival, so cancellations cluster in the days before a stay — but the openings themselves are unpredictable, which is exactly why watching for them beats refreshing the page.

How fast do cancelled sites get rebooked at William O Brien State Park?

At high-demand Minnesota parks a cancelled summer-weekend site is often rebooked within minutes — sometimes under a minute. Being notified the instant it opens, with your Minnesota State Parks login and payment already saved, is the difference between getting in and missing it.

Where do I book a campsite at William O Brien State Park?

Reservations for William O Brien State Park are made on Minnesota State Parks, the official booking system for Minnesota State Parks. GetParkAlerts is independent — we tell you when a site opens; you book it directly on the official site.

Does GetParkAlerts reserve the site for me?

No — we never hold or book sites. We tell you the second one opens so YOU can book it on Minnesota State Parks before anyone else. Booking always happens on the official state system.

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